It's the first time in more than a decade that he's recommended clients purchase the stock.

"After 10 years on the sidelines we are upgrading GE to buy," the Vertical Research Partners analyst said. "We see a path to create equity value."

"It took GE at least 20 years to dig this hole and it will not get out in a year or two. ... While the work ahead is still hard, we think the lack of investor confidence will slowly subside," Sprague added.

Sprague has been a Wall Street analyst for more than 25 years, specializing in industrial research at firms such as Citigroup and Cowen before founding Vertical Partners.

Just before the financial crisis, Sprague in 2007 warned that GE's "size and complexity is working against investor interest." GE's worth had begun to slide at the time, after peaking near $600 billion in August 2000 as one of the most valuable companies in history. Sprague recommended that GE spin off several business units and assets to downsize, or else face "further valuation erosion."

The financial crisis saw GE's value take a sharp hit. Even though GE returned to precrisis levels nearly as quickly as it fallen, shareholder confidence began eroding sharply in January 2017, at about $31 per share.

Under former CEO John Flannery, and continuing under recently named successor Larry Culp, GE has begun breaking up businesses and selling assets – much as Sprague recommended a decade earlier.

GE stock has risen more than 13 percent in the past week. The recent rally began when J.P. Morgan analyst Stephen Tusa upgraded the stock. Tusa had long been bearish on GE. But J.P. Morgan said GE now has a more "balanced risk reward at current levels" and removed the company from a list of stocks it recommended shorting.

Shares were also boosted as the company recently filed paperwork for an initial public offering of its health-care business, people familiar with the matter told CNBC. The stand-alone GE Healthcare is expected as early as next spring and would rank among the largest public companies in the world.